When the centers of pupils are detected in line-of-sight detection or expression detection, the red-eye effect may occur due to low illuminance. In a normal pupil detection method, pupils are detected by using a fact that the brightness of a portion corresponding to a pupil is normally lower than the brightness of a region around the portion in an image. However, when the red-eye effect occurs, the brightness of an image region corresponding to a pupil increases. Thus, when the red-eye effect occurs, pupils cannot be stably detected by the pupil detection method targeted at normal pupils.
To solve the problem, in a technique disclosed in Patent Literature 1, pupils are detected by using a plurality of images captured at different timings while positively causing the red-eye effect occur over the entire pupil.